Your definatly on walking on the right path, that gun is far more advanced than the stuff I did after using LW for only 3 months.. actually I think I was still making lens flares then lol. Overall the gun looks great and it would do mighty fine if it were not a closeup shot.. some edges need to be sharpened up and so on but keep working with it and it will be awesome
If your feel up to it you might want to actually model the grip of the gun too, cause I dont think it will ever look really really good with just texturing.. just a thought.
keep us posted
Matt